A closely integrated series of studies on cognitive and neurophysiological concomitants of normal aging and dementia of the Alzheimer type are proposed. Four interrelated areas are included; neuropsychological assessment electrophysiology, magnetic resonance imaging (MRI). An Administrative and Clinical Core, a Data Management and Statistical Core and an Image Analysis Core will provide assistance with subject recruitment, evaluation and follow-up, scheduling, image analysis and statistical analysis, both within and among projects.